Log positioning apparatus

ABSTRACT

A positioning apparatus for aligning wood logs along a chosen axis in preparation for sawing or other processing in a plane perpendicular to the longitudinal log axis. A pair of transversely spaced grapples are used, each gripping the log securely. One set transversely centers the log with a minimal amount of lifting. The second set also transversely centers the log, and in addition locates the elevation of the log axis along a desired plane regardless of the amount or degree of taper in the log. The first set of grapples uses separate fixed pivotal axes, the second set uses a single grapple axis which is elevationally varied as a function of the degree of closing of the first set.

United States Patent Hayes et al. 1 Feb. 22, 1972 [54] LOG POSITIONING APPARATUS 3,392,765 7/1968 Brookhyser ..144 209 R [72] Inventors: Leonard L. Hayes; Gerald J. Hottinger, Prim ry ExammerHarvey C. Homsby both of Lew'ston Idaho An0meyWells, St. John 81. Roberts [73] Assignee: Potlatch Forests, lnc., Lewiston, Idaho 57 AB T CT S RA [22] Filed: Sept. 28, 1970 L 1 f l d l positioning apparatus or a igning woo logs a ong a chosen [21] PP N04 75,934 axis in preparation for sawing or other processing in a plane perpendicular to the longitudinal log axis. A pair of transver- [52] CL "AM/209 A, 82/25 sely spaced grapples are used, each gripping the log securely. 51 Int. Cl ..B27i 5/00 one set transversely with a minimal [58] Field of Search 144/208 209 209 82/25 lifting. The second set also transversely centers the log, and in 82'/2 7 addition locates the elevation of the log axis along a desired plane regardless of the amount or degree of taper in the log. [56] References Cited The first set of grapples uses separate fixed pivotal axes, the second set uses a single grapple axis which is elevationally UNITED STATES PATENTS varied as a function of the degree of closing of the first set.

2,352,885 7/1944 Bukowsicy 144/208 4 Claims, 6 Drawing Figures 1: E I II I I )7 ZJT l 24 I I I i l I 20 I i" L t; a e .w l 2:. v

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SHEEI 2 (IF 6 INVENTOR. Leann-J L. HI e: Gorclul 1. Ho! inger 1% mam PATENTEDFEB22 I972 SHEET UF 6 INVENTORS Leon'rJ L. H

inger PATENTEI] FEB 2 2 I972 SHEET 5 BF 6 INVENTORS Leann-J L. Hayes Gerald J. Ho'f'finscr 7 BY 7M1, 56444) PATENTEDFEBZZ I972 SHEET 6 OF 6 INVENTORS LOG POSITIONING APPARATUS BACKGROUND OF THE INVENTION The invention set out in this disclosure arose from a modern requirement in plywood operations that the transverse cutting of logs in preparation for their mounting on a plywood lathe be more accurately defined along a plane perpendicular to the log axis. Present procedure simply involves the use of a cutoff saw that engages logs resting on conveyor rolls. Because of the log taper the saw plane is not perpendicular to the log axis, but is slightly inclined. Later, the log axis is oriented coaxially with the veneer lathe axis, and the resulting inclination of the end log faces results in a varying ribbon of veneer waste at each side of the peeled veneer sheet. This ribbon is eliminated by fixed spur knives which trim the side edges of the veneer sheet as it is peeled.

Greater efficiency is now desired in log utilization, and the waste that results from the use of such spur knives to trim these side ribbons can be eliminated if the end surfaces of the log are more accurately developed when the log is cut.

Devices have been previously developed and are in use to hold short lengths of logs during the time they are mounted onto a veneer lathe. These devices support the logs from beneath and use various arrangements for holding the entire log in a preselected position Examples are shown in the prior patents to Bukowsky, U.S. Pat. No. 2,352,885 and Raura, U.S. Pat. No. 3,036,607. However, the cutoff saw that produces the shorter log lengths required by a lathe must operate upon logs of considerable length. The devices of these prior patents are incapable of supporting a log of such length. Therefore, the present device uses grapple arms that positively engage both the lower and the upper surfaces of a log so that a short length of the log can be gripped and be properly oriented while still a part ofa long log.

SUMMARY OF THE INVENTION The invention herein lies in the novel combination of two sets of grapples longitudinally spaced along a supporting framework. These grapples are positioned to operate in planes parallel to a preselected plane, such as the cutting plane of a transverse saw. The first set of grapples are movably mounted to close upon and engage the log surfaces to transversely center the longitudinal log axis relative to the framework. The second set of grapples are also movably mounted to close upon and engage the log surfaces. They also transversely center the longitudinal axis of the log relative to the framework. In addition they are designed to simultaneously vertically position the log axis at a transverse reference line across the grapple elements. A connecting linkage between the grapple elements of the first set and those of the second set are designed so as to elevationally position the second set of grapples relative to the framework and thereby vary the elevation ofthe transverse reference line as a function ofthe degree of closing of the first set of grapples so that the log axis is oriented substantially perpendicular to the chosen plane. This is accomplished regardless of diameter variations or taper in the log, and regardless of whether the log enters the grapple with its large or small end in either direction.

It is a first object of this invention to provide a log positioning apparatus for positively gripping a section of a natural log and orienting the log axis of the section so as to transversely and vertically locate the log axis relative to a preselected transverse plane.

Another object of this invention is to provide such an apparatus which is capable of being adapted to high speed operations in the cutting of logs. Specifically, a minimal amount of vertical movement of the log is required by the embodiment of the invention shown.

Another object of the invention is to provide a mechanically simple apparatus with all of the operating elements thereof directly connected to one another so as to minimize mechanical failure and eliminate the necessity of intermittent adjustment of the various interrelated elements.

These and further objects will be evident from the disclosure that follows, taken together with the accompanying drawings which illustrate a preferred form of the invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of the log positioning apparatus;

FIG. 2 is a top view of the apparatus shown in FIG. I without illustration of the operating cylinder assemblies;

FIG. 3 is a view taken substantially along line 33 in FIG.

FIG. 4 is a view taken substantially along line 4-4 in FIG. 1;

FIG. 5 is a schematic view showing the structure and operation of the set of grapples illustrated in FIG. 3; and

FIG. 6 is a similar schematic drawing illustrating the structure and operation of the set of grapples shown in FIG. 4.

PREFERRED EMBODIMENT The present apparatus is designed to more accurately position logs for the operation of a cutoff saw. A log 10 is partially illustrated in FIG. 1 and 2. The section shown is approximately 8 feet long. It would abut a fixed or movable stop to the left of each drawing and is adapted to be out along a plane shown by the dashed line at 11 by means of a conventional cutoff saw. It may be cut along one or more parallel planes. The log 10 will normally extend outward to the right of the drawing. The initial extension of the log 10 will be several times the portion of its length shown, and will obviously diminish as the log is cut into shorter segments. As illustrated, the log diameter increases from left'to right. The central log axis of the log resting on the conveyor, generally indicated by the dashed line 12, therefore is inclined downwardly from right to left. Where the log is cut in this condition, the cut plane at the end of the log will be slightly inclined from the perpendicular.

The log is fed to the present apparatus by a conventional powered roller conveyor including centering rolls 13. Rolls 13 are driven in unison by gear boxes 14 and interconnecting shafts 15 powered by a conventional driving apparatus (not shown). These rolls 13 serve to move each log longitudinally relative to the instant apparatus and relative to the cutoff saws.

The present apparatus essentially comprises two sets of grapples, the first set being shown in cross sectional detail in FIGS. 3 and 5, the second set being similarly illustrated in FIGS. 4 and 6.

Referring now to FIGS. 3 and 5, the first set of grapples comprises a pair of opposed identical grapple arms 16, I8 which are respectively pivoted to the supporting framework, which includes upper longitudinal channel members 17. The grapple arm 16 is pivotally supported by a fixed bearing shown at 20 (FIG. 2). Arm 18 is fixed to a longitudinal shaft 21 which in turn is journaled by fixed longitudinal bearings at its respective ends, suitably supported by transverse framework members 22. The pivotal axes of the arms l6, 18 are transversely spaced and parallel to one another. In the example shown they are horizontal and perpendicular to the preselected plane 11 along which the log 10 is to be cut.

Each grapple arm is powered so as to be moved in overlapping opposed relationship to one another. This is accomplished by means of double acting hydraulic cylinder assemblies 23, 24 which respectively moves arms 16, 18. Each hydraulic cylinder assembly is pivotally connected to the framework at 25 and to the respective arm which it powers at 26. These pivotal axes are parallel to the pivotal axes of arms 16 and 18 relative to the supporting framework. The controls (not shown) that operate cylinder assemblies 23, 24 serve to move each assembly in unison.

The second set of grapples is shown in FIGS. 4 and 6. It includes a pair of opposed grapple arms 27, 28, pivoted by bearings 30 about a common longitudinal horizontal axis parallel to the axes of arms l6, 18. The bearings 30 are supported by a crank 31 fixed to and extending radially outward from the shaft 21. The arms 27, 28 are powered by double acting hydraulic cylinder assemblies 32, 33, pivoted to the framework at 34 and to the respective arms at 35. The cylinder assemblies 32, 33 are also operated in unison with one another.

The two sets of grapple arms are longitudinally displaced from one another and each engages only a short longitudinal portion ofa log 10. They are operated in such fashion that the arms 16, 18 first fully engage the log and then arms 27, 28 are activated to also fully engage the log 10. In general, the arms 16, 18 are designed to grasp the log securely with the log in a transversely centered position immediately adjacent to the rolls 13. The arms 16, 18 are designed to only slightly life the log 10. After such engagement, the second set of grapple arms 27, 28 then grasp the log to also transversely center the log. In addition, the interconnection of the grapples through shaft 21 results in the elevational positioning of the arms 27, 28 to locate the central longitudinal axis of the log in a horizontal plane, assuming that the preselected plane 11 is a vertical plane.

The above results are achieved due to the generation of the log engaging surfaces on the arms 16, 18 and 27, 28. The contour of the arms is shown in detail in FIGS. 3-6 in relation to the maximum diameter of log engaged thereby, the minimum diameter of log engaged thereby and an intermediate diameter. In FIG. 3 and 4 the grapples are shown in full lines in a fully open or released position and in dashed lines when grasping a minimal size log. In FIGS. 5 and 6, which are somewhat schematic, the grapples are shown in full lines when grasping a maximum size log and in dashed lines when grasping an intermediate sized log.

Referring to FIGS. 3 and 5, the lower log engaging surface 36 of each arm I6, 18 is essentially a continuous are centered about the pivotal axis of the arm on the supporting framework. In FIG. 5, these axes are designated for arms 16, 18 as 37, 38 respectively. The exact center of the arc defined by surface 36 might be slightly offset from these axes, depending upon the precise design characteristics required. Because of the continuous arc, the lower surface of each log engaged along the surface 36 will be held at a substantially common elevation. The center axes of the logs will therefore vary in elevation depending upon the diameter of the log. The upper log engaging surface 40 of each arm 16, 18 is generated to match the circular surface configuration of the various sizes of logs falling within the range of design of the apparatus. The contour of the surface 40 matches the log contour as each size log rests on surface 36.

The lower and upper surfaces 41, 42 on the arms 27,28 are centered to each side of an arc 44 on each arm generated about the axis 43 (FIG. 6) about which arms 27, 28 are pivotally mounted on the crank 31. A circular log section grasped between the opposed arms 27, 28 will have its central axis on the arc 44, regardless of its diameter. The surfaces 41, 42 are generated so as to maintain this constant relationship between the center ofa circular cross section engaged thereby and the pivotal axis 43, for the entire range of log diameters. As shown in FIG. 6, the center of the maximum size log diameter at 45 is located on the arc 44. In dashed lines, the center of the intermediate sized log at 46 is similarly located with respect to the are 44, which is lower in elevation due to the repositioning of crank 31 and axis 43, the repositioned location ofaxis 43 being shown at 43 A.

The geometry of the arms and the crank 31 is such that the degree of closing of arms 16, 18 results in horizontal alignment of the log central axis upon subsequent closing of arms 27,28. As shown, the axis 43 for the arms 27, 28 is lowered in response to increased amounts of closing of the arms l6, 18. The cooperative operations of the two sets of grapples therefore results in the transverse and vertical alignment of the central log axis with respect to the cutting plane 11.

The desired alignment of the log axis is independent of the amount of taper in the log or the direction of taper. The arms 16, 18 locate the bottom of each log at a substantially identical elevation. This in turn locates the center of each log at an elevation directly related to its diameter at the portion engaged by arms 16, 18. The engagement of the log directly controls the angular position of crank 31 on shaft 21 and there fore the elevation of the axis 43 and arc 44 previously described. Because of the closed arms 27, 28 are designed to locate the center of the log portion engaged thereby along the arc 44, the chosen relationship of the elements insures the proper horizontal alignment of the log axis, whether the end of the log engaged by the grapple arms 27, 28 is smaller than that engaged by arms 16, 18 or is larger. The geometric development of the arms is such that the arc 44 serves as a transverse reference line across the second set of grapples along which the log axis will be ultimately positioned at a central location.

A log 10 when grasped by the two sets of grapples can be cut at either or both ends along a plane that will be substantially perpendicular to the log axis. Because the grapples grip the log securely it is immaterial as to how much additional length of the log extends outwardly from the apparatus shown. The structure is equally applicable to instances which require the holding and positioning of short logs or longer extensions. In addition, because the grapples require only minimal lifting of the logs, the time necessary to pick up the logs is held to a minimum and the resulting damage to the logs from dropping when released by the grapples is also minimized.

Many minor changes might be made in the above description without deviating from the basic concept of the invention, which lies in the interrelation of the two sets of grapples. These might involve the specific structural details of the arms, bearings, and other methods of moving the arms to grasp the logs.

Having thus described my invention, I claim:

1. An apparatus for positioning the central longitudinal axis of a tapered longitudinal member relative to a preselected transverse plane, comprising:

a rigid supporting framework;

first grapple means movably mounted to said framework for closing upon and engaging the sides of the member and having contoured surfaces for transversely centering the longitudinal axis thereof relative to said framework;

second grapple means movably mounted to said framework at a location longitudinally displaced from said first grapple means for closing upon and engaging the sides of the member and having contoured surfaces for transversely centering the longitudinal axis thereof relative to said framework while simultaneously vertically positioning the longitudinal axis at a transverse reference line across said second grapple means;

and means interconnecting said first and second grapple means for elevationally positioning said second grapple means relative to said framework to thereby vary the elevation of the transverse reference line as a function of the degree of closing of said first grapple means in such fashion that the central longitudinal axis of said member when engaged by both of said first and second grapple means is perpendicular to the preselected transverse plane.

2. The apparatus as set out in claim 1 further comprising:

first and second hydraulic cylinder assemblies respectively connected between said framework and said first and second grapple means for selectively closing said grapple means about an object.

3. An apparatus for positioning the central longitudinal axis of a log section relative to a vertical plane, comprising:

a rigid supporting framework;

a first pair of opposed upright grapple arms pivotally mounted to said framework about axes perpendicular to said plane, said first pair of grapples each having lower contoured log engaging surfaces which locate a log gripped thereby with its lowermost surface at a constant elevation;

a second pair of opposed upright grapple arms pivotally 4. An apparatus as set out in claim 3 wherein said first pair mounted to said framework about a common axis perpenof grapple arms are pivotally mounted to said framework dicular to said plane, said second pair of grapples each about individual tr n r ly Spaced 8X68; having contoured log engaging surfaces which locate a Said mechanicauinkage comprising log gripped thereby with its central longitudinal axis inter- 5 a Shaft fixed to one ofsaid first P Ofgrapple arms and secting a reference line across the grapple arms thereof; ing its Shaft axis located coaxially with the Pivotal axis of and a mechanical linkage joining at least one of said first Said one a crank fixed to and projecting radially outward from said shaft; 10 and bearings pivotally mounting said second pair of grapple arms to said crank about an axis parallel to the shaft axis.

pair of grapple arms and movably supporting said second pair of grapple arms relative to said framework, whereby the elevation of the reference line across said second pair of grapple arms varies responsive to pivotal movement of said first pair of grapple arms. 

1. An apparatus for positioning the central longitudinal axis of a tapered longitudinal member relative to a preselected transverse plane, comprising: a rigid supporting framework; first grapple means movably mounted to said framework for closing upon and engaging the sides of the member and having contoured surfaces for transversely centering the longitudinal axis thereof relative to said framework; second grapple means movably mounted to said framework at a location longitudinally displaced from said first grapple means for closing upon And engaging the sides of the member and having contoured surfaces for transversely centering the longitudinal axis thereof relative to said framework while simultaneously vertically positioning the longitudinal axis at a transverse reference line across said second grapple means; and means interconnecting said first and second grapple means for elevationally positioning said second grapple means relative to said framework to thereby vary the elevation of the transverse reference line as a function of the degree of closing of said first grapple means in such fashion that the central longitudinal axis of said member when engaged by both of said first and second grapple means is perpendicular to the preselected transverse plane.
 2. The apparatus as set out in claim 1 further comprising: first and second hydraulic cylinder assemblies respectively connected between said framework and said first and second grapple means for selectively closing said grapple means about an object.
 3. An apparatus for positioning the central longitudinal axis of a log section relative to a vertical plane, comprising: a rigid supporting framework; a first pair of opposed upright grapple arms pivotally mounted to said framework about axes perpendicular to said plane, said first pair of grapples each having lower contoured log engaging surfaces which locate a log gripped thereby with its lowermost surface at a constant elevation; a second pair of opposed upright grapple arms pivotally mounted to said framework about a common axis perpendicular to said plane, said second pair of grapples each having contoured log engaging surfaces which locate a log gripped thereby with its central longitudinal axis intersecting a reference line across the grapple arms thereof; and a mechanical linkage joining at least one of said first pair of grapple arms and movably supporting said second pair of grapple arms relative to said framework, whereby the elevation of the reference line across said second pair of grapple arms varies responsive to pivotal movement of said first pair of grapple arms.
 4. An apparatus as set out in claim 3 wherein said first pair of grapple arms are pivotally mounted to said framework about individual transversely spaced axes; said mechanical linkage comprising: a shaft fixed to one of said first pair of grapple arms and having its shaft axis located coaxially with the pivotal axis of said one arm; a crank fixed to and projecting radially outward from said shaft; and bearings pivotally mounting said second pair of grapple arms to said crank about an axis parallel to the shaft axis. 